Jean Noel Nyemb

Jean Noel Nyemb
University of Maroua · Department of Refining and Petrochemistry

PhD in Organic Chemistry
looking for collaborators in compounds isolation, purification, structure elucidation, and bioactivities, writing papers

About

29
Publications
13,762
Reads
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177
Citations
Additional affiliations
September 2016 - September 2017
COMSATS University Islamabad
Position
  • Researcher
Description
  • TWAS PhD research Fellow
March 2013 - December 2019
University of Yaounde I
Position
  • PhD Student
October 2012 - present
University of Ngaoundere
Position
  • Lecturer
Education
March 2013 - December 2019
University of Yaounde I
Field of study
  • Organic Chemistry - Natural Products Chemistry

Publications

Publications (29)
Article
A reinvestigation of the roots of Strychnos icaja resulted in the isolation of a new bisindole alkaloid named strychnobaillonine (1) with original C-17-N-1' and C-23-C-17' junctions, in addition to sungucine, bisnordihydrotoxiferine, and strychnohexamine (2). Compound 1 showed potent activity against the chloroquine-sensitive 3D7 strain of Plasmodi...
Article
Full-text available
Objective: To obtain a scientific basis of the use of plant-derived preparations by many rural people in Cameroon, for their primary health care needs in the treatment of diseases such as cancer. Methods: The antiproliferative effect of 11 plants methanol crude extracts on four cancer cells using sulforhodamine-B assay and their antioxidant acti...
Article
Full-text available
Aims: The aim of the present study was to evaluate the total phenolics and flavonoids content of stem barks of Vitellaria paradoxa C. F. Gaertn., and identify its main chemical constituents. Methodology: V. paradoxa stem barks were extracted by maceration with methanol. Preliminary phytochemical screening was performed on the crude methanol extract...
Article
An aliphatic alkene namely pentapentacontene (4) was isolated for the first time from a natural source, Gardenia aqualla, along with fourteen other compounds including nonacosanol (1), tetratriacontanol (2), octatriacontanol (3), β-sitosterol (5) and stigmasterol (6), daucosanol (7), ursolic acid (8), uvaol (9), 3β,19α,23β,24α-tetrahydroxyurs-12-en...
Article
Full-text available
Two phytosphingosine-type ceramides (euclinide A (1) and B (2)) were isolated alongside one fatty acid (geddic acid (3)), one fatty acid-1-glyceride ((2 S)-1- O-hentriacontanoyl glycerol (4)), ten triterpenes ( α-amyrin (5), α-amyrin acetate (6), ursolic acid (7), β-amyrin (8), β-amyrin acetate (9), β-amyrin palmitate (10), oleanic acid (11), masli...
Article
Full-text available
The aim of this work was to isolate, characterize, and evaluate the antioxidant activity as well as the phytotoxicity of the crude extracts and pure compounds obtained from C. febrifuga. Nine compounds were isolated from leaves, stem bark and roots crude extracts (methylene chloride/methanol: 1/1) after repeated silica gel column chromatography. co...
Article
Full-text available
A new cerebroside namely Campanulatoside (1) was isolated from the stem bark of S. campanulata along with seven known compounds including ursolic acid (2), oleanolic acid (3), 3-(3',4'-methylenedioxyphenyl)-2,3-epoxypropanol (4), spinasterol (5); stigmasterol (6); campesterol (7) and α-D-Glucopyranosyl-O-(1α2)-α-D-fructofuranoside (8). The structur...
Article
Full-text available
Leptadeniamide, new ceramide (1) together with six known compounds (2-7) have been isolated from the leaves extract of Leptadenia hastata. Their structures were established using IR, NMR 1D (1 H and 13 C) and 2D (COSY and HSQC) spectroscopy, mass spectrometry and by comparison with related data reported in the literature. The antimicrobial activity...
Article
Full-text available
The present study was conducted to determine the antioxidant activity and chemical components of Ficus abutilifolia. Miq. (Moraceae). The study were performed at Department of chemistry, University of Ngaoundere, Cameroon, between July 2017 and September 2018. Phytochemical study was carried out on all extracts of stem barks. Besides, the total phe...
Article
Full-text available
The aim of this work was to evaluate in vitro antiradical scavenging activity of propolis from Nkambe (North-West, Cameroon). The polyphenol content of the acetone extract was evaluated using the Folin-Ciocalteu reagent as 0.166±0.008 gGAE/100 gRM. Antiradical scavenging activity of hexane and acetone extracts was carried out on DPPH using ascorbic...
Article
Full-text available
Medicinal plants have been of great importance to many traditional communities for many generations. However, there is need to carry out scientific studies in order to confirm the medicinal properties of many plants used traditionally. Cosmos sulphureus (Asteraceae) used by local communities for the treatment of various diseases has showed antioxid...
Article
Full-text available
Phytochemical investigation of the ethanol extract of the stem bark of Hypericum lanceolatum Lam. (Guttifereae) afforded eight known compounds including 2,2ʹ,5,6ʹ-tetrahydroxybenzophenone (1), 5-hydroxy-3-methoxyxanthone (2), 3-hydroxy-5-methoxyxanthone (3), betulinic acid (4), hydroquinone (5) 6,7-dihydroxy-1,3-dimethoxyxanthone (6), calophyllumin...
Article
Full-text available
Two samples of Cameroonian propolis from Nyambaka (Adamawa) and Mveg (Nord-West) were collected for some analysis. Six extracts were obtained by simple maceration with solvents of increasing polarity: hexane, ethyl acetate (EtOAc) and the MeOH/H2 O (80:20, v/v). Liquid Chromatography coupled with Mass Spectrometry (LC-MS) analysis revealed the pre...
Article
Full-text available
In the North of Cameroon, Boswellia dalzielii is a medicinal plant used in traditional medicine to treat infectious diseases (dysentery, typhoid, cholera and malaria). The aim of this study is to identify and characterized the bioactive compounds from the roots of this plant. The methanol crude extract from the root of Boswellia dalzielii Hutch was...
Article
Full-text available
Abstract: Gardenia aqualla a plant of the Rubiaceae family is being used extensively in Africa, particularly in Cameroon as an herbal medicine. Therefore it is necessary to have knowledge of the constituents of the plant of our native species. Thus, the aim of the present study was to investigate chemical constituents of this herbal medicine. Nine...
Article
Full-text available
The optimal conditions of Microwave-Assisted Extraction (MAE) of total phenol content and total flavonoids content from A. occidentale L. stem bark were determined. A second-order regression for central composite design (CCD) was used to investigate the effects of four independent variables, namely extraction time (s), irradiation power (W), solven...
Article
Full-text available
Objective: To investigate the phytochemical constituents, antioxidant and anthelmintic activities of the crude methanol extract of Cissus populnea (C. populnea) rhizomes. Methods: Phytochemical screening was performed using standard protocols, and column chromatography of silica gel was used for the compounds isolation. DPPH antiradical scavenging...
Article
Full-text available
Bergenin (1) was isolated as the major compound of the Roots of Cissus populnea. Its structure was elucidated on the basis of spectral analysis, including 1D and 2D NMR experiments and Mass Spectrometry (MS) as well as by comparison with available data in the literature. Bergenin (1) was evaluated for its antimicrobial activity against four bacteri...
Article
Full-text available
A new cerebroside (2R)-2-hydroxy-N-[(Z,2S,3S,4R)-1-O-β-D-glucopyranosyl-3,4-dihydroxynonadec-8-en-2-yl] nonacosanamide (1) was isolated from the wood of roots of V. paradoxa along with six known compounds including catechin (2), quercetin (3), spinasterol 3-O-β-D-glucopyranoside (6), gallic acid (7) and a mixture of β-sitosterol (4) and stigmastero...
Article
Full-text available
A new cerebroside (2R)-2-hydroxy-N-[(Z,2S,3S,4R)-1-O-β-D-glucopyranosyl-3,4-dihydroxynonadec-8-en-2-yl] nonacosanamide (1) was isolated from the wood of roots of V. paradoxa along with six known compounds including catechin (2), quercetin (3), spinasterol 3-O-β-D -glucopyranoside (6), gallic acid (7) and a mixture of β-sitosterol (4) and stigmaster...
Article
Full-text available
Typhoid fever remains a marked problem of public health in the world especially Africa and Asia. This work aimed to evaluate the antisalmonellal potential of extracts and fractions from Tristemmamauritianum. The microdilution technique was used for MIC and MBC determination whereas GC/MS was used to identify some components of the methanol extract....
Article
Full-text available
Objective: To investigate the anticancer and antioxidant potential of methanol bark extract of Ziziphus mauritiana (Z. mauritiana), which is used by traditional healers to cure some cases of cancer in Cameroon. Methods: The methanol crude extract of Z. mauritiana has the antiproliferative activity on four cancer cell lines and its antioxidant activ...
Article
Full-text available
4-hydroxycinnamate ester namedn-triacontyl-4-hydroxy cinnamate (1) and long chain alkanoic ester named ntriacontylpropanoate (2), together with 4 known compounds were isolated from the stem bark of Vepris heterophylla. The structures of the two compounds were determined by comprehensive analyses of their 1D and 2D NMR, mass spectral (EI and ESI) da...

Questions

Questions (3)
Question
I have 1H NMR spectrum of several compounds recorded in DMSO in which protons of hydroxyl groups resonate as doublet (for an -CHOH-) or triplet (for -CH2OH-). Usually I know that those type of protons appear as singlets, so why in DMSO they appear like mentioned above?
Question
Does anyone help me for the interpretation of LC-MS chromatogram?

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Projects

Project (1)
Project
Isolation, Structural elucidation of the chemical constituents of the plants. Antioxidant activity Anti-Diabetic activity (Glucosidase inhibition, ALR1, ALR2) Anti-cancer activity Antiplasmodial activity Antimicrobial activity